The present invention relates to bone plates. In particular, the present invention relates to a bone plate for fixating fractures of a proximal humerus bone and a bone plate for fixating fractures of a distal radius bone.
The proximal humerus comprises the upper portion of the humerus, i.e. upper arm of the human body, commonly known as the shoulder area. Fractures of the proximal humerus typically result from traumatic injuries such as sporting accidents and can be more frequent with age due to bone loss. Fractures of the proximal humerus are treated by exposing the fracture site and reducing the bone fracture and then placing a plate or other means onto the bone to fixate the fracture for healing in the reduced position. Reducing the fracture includes realigning and positioning the fractured portions of the bone to their original position or similar stable position. Fixating the fracture includes positioning a plate over the fractured portions and securing the plate onto the fractured bones and adjacent nonfractured bones with bone screws.
Conventional fixation plates have several shortcomings when applied to the proximal humerus. First, the most common conventional plate used for fixating proximal humerus fractures is the AO T-plate which is not specifically adapted for the proximal humerus. The AO T-plate is a thick plate which cannot be contoured nor bent to fit the proximal humerus bone. It can only be used with large screws. The size of the screw heads may cause impingement under the acromion process.
In addition, while not common, the cloverleaf plate, which is specifically adapted for use in fixating fractures of the tibia and ankle area, has been adapted for fixating the proximal humerus. In order to use the cloverleaf plate for the proximal humerus, a head portion of the cloverleaf plate must be bent and cut to fit the proximal humerus. Frequently, the bending and cutting of the plate creates a stress concentration or worsens an existing stress concentration in the bone plate. These stress concentrations regularly lead to a fatigue failure of the plate when fixed on the proximal humerus for an extended period of time. Moreover, bending and cutting the cloverleaf plate to the proper shape is quite difficult and is not readily accomplished. At best, a rough approximation of the shape of the curvature of the proximal humerus is attempted while the plate still does not adequately cover the greater tuberosity 18 and transition from the proximal humerus shaft 15 to the greater tuberosity 18.
Moreover, in some instances where there are three and four part fractures and a combined fracture and dislocation of the proximal humerus (from the joint space), the common techniques of open reduction and internal fixation are particularly inadequate. In these instances, the conventional response is to replace the fractured bone portion with a prosthetic implant, e.g. artificial proximal humerus, instead of reducing and fixating the fractured area. This approach has been favored in treating four part fractures and fracture dislocations due to the difficulty of managing the reduction with complicated fracture patterns and the difficulty of adapting available plates for fixation in these situations. Nevertheless, because the artificial replacement of a proximal humerus requires significantly more surgery and expense, and since it is preferable to preserve the natural bones whenever possible, it would be desirable to treat these more difficult cases with open reduction and internal fixation with a bone plate.
Moreover, the proximal humerus is not the only location of the body that presents a challenge of open reduction and internal fixation for multiple fractures and/or partial dislocations from a joint space. Specifically, the distal radius area (commonly referred to as the wrist area) is the site of many multiple fractures. However, like the proximal humerus, a lack of available bone plates that are especially adapted to volar (palm side) and especially adapted to dorsal (top side, opposite the palm) hinder regular and successful treatment by fixation of multiple fractures of the distal radius. Both the volar and dorsal aspects of the distal radius have different anatomical structures and therefore commonly require different adaptions when using a single type of conventional plate to treat both locations. Moreover, conventional plates are not conducive to bending by the surgeon without creating a stress concentration or worsening an existing stress concentration in the plate.
Further, in each of these situations (fractures of the proximal humerus, dorsal distal radius, and volar distal radius), the reduction of the fractured bones is done by free hand without a guide or tool or with K-wires to assist in insuring the return of the fractured portions to their proper location. Where a single fracture occurs, the original position of the fractured portion can be easily recognized and the unfractured portion functions as a guide or reference point for reducing and fixating the fractured portion to the unfractured bone portion. However, this challenge is more acute with three and four part fractures, and fracture dislocations since no single portion of the bone remains unfractured. Therefore, no single portion of the fractured bone can act as a stable guide or reference to insure the return of the fractured portions to their proper position and to remain stable to enable proper reduction and fixation of the multiple fractured portions at the same time.